Obtaining 3-dimensional shape of textured and specular surfaces using four-source photometry

Robust estimation of surface properties and interpolation of shadow/specularity components

“…7 However, the present method, Method:LMS+RBF, does quite well, in fact regenerating image data at about the same PSNR as for the noisy data used compared to perfect synthetic data. But notice that, if we did indeed use the simpler QUANTILE method for detecting shadow-and specular-weighted pixels, we would nonetheless arrive at just the same median PSNR for output images, provided we utilized RBF interpolation for the non-matte part of an interpolation image -i.e., provided we use Method:QUANTILE+RBF.…”

“…Their aim is to detect specularities and exclude them from normal and albedo reconstruction. The main idea behind this algorithm is as in [12] with the addition of a smoothness constraint on the albedo. Their method is robust to outliers under the condition that only a small number of images is supplied.…”

“…Early efforts at specularity detection in PST [7,8,9] used four lights and excluded values yielding significantly differing albedos. Rushmeier et al [10] used a similar, 5-light approach.…”

Photometric stereo with non-parametric and spatially-varying reflectance

“…For example, it has been observed that the reflectance of many materials is well approximated by the sum of a specular and a diffuse lobe, which has motivated an entire line of research [4,2,11,15]. Many of these approaches assume a Lambertian diffuse lobe, while not imposing a parametric form on the specular lobe.…”

“…Many of these approaches assume a Lambertian diffuse lobe, while not imposing a parametric form on the specular lobe. Examples include Coleman and Jain [4] and Barsky and Petrou [2] who treat specular pixels as outliers as well as Schlüns and Wittig [20], Sato and Ikeuchi [19], and Mallick et al [14] who assume the color of the specular lobe differs from the color of the diffuse lobe, allowing separation of the specular and diffuse components.…”